Gel trough removing device

ABSTRACT

GEL TROUGHS IN ELECTROPHORETIC GEL MEDIA ARE REMOVED WITH AN IMPLEMET COMPRISING A FINGER GRIPPABLE HANDLE, AN ELONGATED FLEXIBLE NARROW GAUGE WIRE EXTENDING OUTWARDLY FROM ONE END AND A REDUCED BLADE PORTION AT THE OTHER END, SAID WIRE TERMINATING IN A SHORT U-SHAPED, DOWNWARDLY DISPOSED BEND TRANSVERSE TO THE AXIS OF SAID WIRE, SAID BEND HAVING AN INNER WIDTH BETWEEN ITS VERTICAL LEGS SLIGHTLY LESS THAN THE WIDTH OF SAID TROUGH AND THE HEIGHT OF THE VERTICAL LEGS OF SAID BEND BEING GREATER THAN THE DEPTH OF SAID TROUGH.

July 16, E V, M|RANDA ET AL GEL TROUGH REMOVING DEVICE 2 Sheets-Sheet J.

Filed Oct. 3, 1973 July 16, 1974 E. V MIRANDA ETI'AL GEL THOUGH REMOVING DEVICE 2 Sheets-Sheet 2 Filed Oct. 5, 1975 M QM United States Patent 3,824,165 GEL TROUGH REMOVING DEVICE Eduardo V. Miranda and Lamont J. Seitz, Huntington Beach, Calif., assignors to Baxter Laboratories, Inc., Morton Grove, Ill.

Filed Oct. 3, 1973, Ser. No. 402,950 Int. Cl. B01k 5/00 US. Cl. 204-180 G 6 Claims ABSTRACT OF THE DISCLOSURE Gel troughs in electrophoretic gel media are removed with an implement comprising a finger grippable handle, an elongated flexible narrow gauge wire extending outwardly from one end and a reduced blade portion at the other end, said wire terminating in a short U-shaped, downwardly disposed bend transverse to the axis of said wire, said bend having an inner width between its vertical legs slightly less than the width of said trough and the height of the vertical legs of said bend being greater than the depth of said trough.

This invention relates to an implement for use with gel electrophoresis and, more particularly, to a gel trough removing tool.

The separation of materials by electrophoresis is a well known laboratory procedure. Electrophoresis is the movement in an electric field of charged particles such as, for example, inorganic ions, proteins such as albumin, en- Zymes, hemoglobin, blood serum, carbohydrates and the like substances in a suitable transport medium. These charged particles, as constituents of particular mixtures will migrate with different mobilities when the mixture in solution is placed in an electric field. While the current is flowing, the charged particles will move continuously at variable velocities and separate into different groups or patterns and thereby provide an effective means for resolving the components of certain mixtures.

Various types of migration support media for the electrophoretic separation of biological and other such substances are known, for example, elastic hydrophilic gel materials such as agar, agarose, polyacrylamide and starch, and more rigid materials such as cellulose acetate strips, filter paper and various other microporous films.

The present invention is concerned with electrophoretic separations which empoly gel materials as the migration support media. Typical devices for carrying out such gel electrophoretic separations are those described, for example, in US. Pats. 3,047,489; 3,129,158; 3,407,133; 3,563,- 880; 3,578,604; 3,674,678; 3,715,295; 3,718,436; and 3,736,100. Conventional gel materials used in these devices such as agar are further described, for example, in US. Pats. 2,843,540; 3,062,731; and 3,497,437.

Ordinarily, in such devices the molten gel material is poured in a shallow, open receptacle, plate or tray and allowed to solidify upon cooling and thereby form a semisolid gel medium. Subsequently, circular wells and/or elongated troughs are punched or otherwise formed in the gel for the placement of blood specimens, antisera or other such biologically reactive substances. In the case of circular wells, the wells can be conveniently formed in a predetermined pattern by punching holes through a template, such as shown in FIG. 4 of U.S. Pat. 3,407,133, with a suitable punch or drill.

On the other hand, the formation of an elongated trough in the gel is attendant with various difficulties and problems. In conventional practice, the trough is cut with a die or knife and then a wooden probe such as toothpick is used to remove the cut gel portion from the trough zone. This procedure, however, is very inconvenient and tedious and frequently results in imperfectly formed troughs which can undesirably afiect the accuracy of the electrophoretic migration patterns. -If the laboratory technician is not very precise in using the wooden probe, the wall of the gel in the trough will become gouged and torn.

In immune-electrophoresis, both circular wells and elongated troughs are desired in the gel tray, Protein samples or other such fluid biological specimens are placed in the wells and the tray is then electrophoresed. Distinct zones are formed as the proteins migrate according to their individual mobilities during the electrophoresis. Subsequently, the elongated troughs are filled with anti-body or other such fluid biological substances and the gel tray is incubated to allow both the separated proteins and the anti-body to diffuse through the gel and combine to form the characteristic arc-shaped immuno-electrophoretic patterns. However, because of the sequence in which the electrophoretic and diffusion reactions are carried out, it is desirable for the manufacturer to supply gel trays with only the circular wells cut out completely and to provide means for the operator to remove gel strips to form the elongated troughs after the initial electrophoretic reaction is completed. Imprecise results frequently occur when the elongated troughs are pre-formed and open during the initial electrophoretic reaction due to spillage of fluid sample or buffer material into the trough during handling of the tray.

It is, however, convenient for the manufacturer to make the elongated cuts on both sides of the trough and to leave the two ends of the trough uncut whereby the gel strip will remain in position during shipment and handling prior to the diffusion reaction. It is then desirable to provide the operator with convenient means to remove the gel strip and thereby form the elongated troughs.

Accordingly, it is an object of the present invention to provide an improved method of removing a gel trough strip in electrophoretic gel media.

It is another object of the present invention to provide a novel gel trough removing implement for use with gel electrophoresis devices.

It is yet another object of the invention to provide a gel trough removing tool which is self-guiding along the walls of the trough.

Other objects and advantages of the invention will be apparent to the person skilled in the art after reading the description hereof.

Briefly stated, the gel trough removing tool of this invention comprises a finger grippab'le handle, an elongated, flexible narrow gauge wire extending outwardly from one end and a reduced blade portion terminating in a knife edge at the other end of said handle, said knife edge having a length substantially the same as the width of the trough to be cut, said wire terminating in a short U- shaped, downwardly disposed ben-d transverse to the axis of said wire, said bend having an inner width between its vertical legs slightly less than the predetermined width of said trough and the height of the vertical legs of said bend being greater than the predetermined depth of said trough.

While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter regarded as forming the present invention, it is believed that the invention will be better understood from the following exemplary description taken in connection with the accompanying drawings in which:

FIG. 1 is a perspective view showing the elements of the gel trough removing tool of the invention in operation. FIG. 2 is a side view of the gel trough removing tool. FIG. 3 is a top view of the gel trough removing tool.

FIG. 4 is a front end view of the gel trough removing tool.

FIG. 5 is a rear end view of the gel trough removing tool.

a FIG. 6 is a side view of another embodiment of the gel trough removing tool.

FIG. 7 is a top view of the gel trough removing tool of FIG. 6.

FIG. 8 is a front end view of the gel trough removing tool of FIG. 6.

FIG. 9 is a rear end view of the gel trough removing tool of FIG. 6.

Referring now to the drawings, particularly to FIGS. 1 to 5, the gel trough removing tool is generally indicated by 11 and comprises handle 12, elongated wire 13 and blade 14. Handle 12 in the illustrative embodiment shown in the drawings has a generally rectangular parallelepiped configuration in which sides 15 and 16 are adapted for finger gripping. Sides 15 and 16 can also be concave to further facilitate such finger gripping.

Extending outwardly from forward end 17 of handle 12 is elongated wire 13. Wire 13 has a short U-shaped bend 18 at its distal end. Bend 18 is downwardly disposed and transverse to the axis of wire 13. The height of vertical legs 19 and 20 of bend 18 should be at least slightly greater than the depth of trough 27 to be removed in the gel layer of tray 26. In the embodiment illustrated in the drawings, leg 19 is slightly longer than leg 18 in order to provide adequate clearance for handle 12 as it passes over tray 26 during use of the gel trough removing tool.

Since the gel thickness in the tray is about 0.05-0.l inch, and preferably about 0.06 inch, the height of legs 19 and 20 need only be slightly greater than said thickness. However, due to the difliculty in making such a short bend with a wire of the desired gauge, the height of legs 19 and 20 generally will be at least about 0.2 inch. The height of legs 19 and 20 can be as great as about one inch but use of greater heights results in awk- Ward and inconvenient operation of tool 11 in practice.

The gauge and length of wire 13 are adapted to provide flexibility whereby the wire is self-guiding along the walls of the trough and yet is sufiiciently rigid to overcome the resistance of the gel in operation of tool 11. A length of about 1-3 inches is preferred and 2 inches is most preferred. A wire of substantially greater length is too difficult to guide in the trough, and a wire of substantially shorter length is not of sufii cient flexibility, to compensate for the normal unsteadiness of the hand in manual operation.

The gauge of wire 13 also must be such that the sum of two diameters of wire 13 and one width of the trough will be only slightly greater than the width of the trough itself. This unique relationship is dependent on the requirement that the width of the gel strip removed from the trough must fit in the space 21 and yet the dimension 23 (which includes space 21 plus two diameters of wire 13 indicated by reference numerals 22) must not be substantially greater than the width of the trough itself. The natural elasticity of the gel permits the dimension 23 to have a width slightly greater than the width of the trough and permits dimension 21 to have a width slightly less than the width of the trough. The sum of these two differences in widths is equivalent to the sum of two diameters 22 of wire 13.

Since the trough width in the electrophoretic unit is about 0.050.l inch, and preferably about 0.06 inch, the wire preferably has a gauge of about 0.0l0.018 inch, and most preferably about 0.014 inch.

In an illustrative example, the width of the trough is 0.06 inch, the gauge of the wire is 0.014 inch, and the dimension 23 is 0.080 inch. This leaves a width 21 between legs 19 and 20 of 0.052 inch, which is slightly less than the 0.06 inch width of the gel strip to be removed from the trough. The elasticity of the gel permits slight compression to accommodate these differences in widths.

Extending outwardly from rear end 24 of handle 12 is a reduced blade portion 14 'which gradually tapers in width and length to a knife edge 25. Knife edge 25 preferably is transverse to the axis of wire 13. The length of edge 25 should be substantially the same as the predetermined width (indicated at ends 28 and 29) of trough 27 to be removed in gel 30. Thus, in use of the gel trough removing tool 11, edge 25 will be depressed in the surface of gel 30 at ends 28 and 29 and transverse to the length of trough 27 so that it will form the cut ends of the trough. The gel strip then will be free for removal by the elongated wire end of tool 11. l

Handle 12 can be made of any rigid material, for example, a thermoplastic resinous material. Wire 13 thereby can be placed in the die during fabrication and then handle 12 can be conveniently molded around the wire. Wire 13 preferably has a bend 30, for example a angle bend, at the end of its attachment to handle 12 to provide a firm anchor when embedded within the handle.

In the embodiment of the gel trough removing tool shown in FIGS. 6 to 9, handle 31 comprises a rigid paperboard enclosure. Extending outwardly from rear end 32 of handle 31 is a reduced blade portion 34 which comprises a generally U-shaped extension of wire 33. In this embodiment, knife edge 35 is that portion of wire 33 which lies between the two bends of the U-shaped extension of wire 33. These can be about 90 angle bends although the top bend preferably is slightly greater than 90, for example, about to The end portion 36 of wire 33 will thereby have a suitable separation from intermediate portion 37 of wire 33 for convenient placement and anchoring within handle 31. Handle 31 can comprise two rigid sheets of paperboard, or a single foldable sheet of paperboard which is folded lengthwise at the center, to form the two sides of said handle. Wire portions 36 and 37 are then held in place between the two paperboard sides of handle 31 by a suitable adhesive bonding material. The inner sides of the paperboard pieces can have a pressure sensitive adhesive coating and the two pieces can be brought together to capture the wire portions 36 and 37 which are thereby embedded in handle 31.

It will be understood that although paperboard and thermoplastic resins are illustrated herein, the handle is not limited to these materials of construction and other suitable rigid materials can also be used for fabrication of the handle.,

In the operation of the gel trough removing tool and in practicing the method of the invention, as can be seen best from FIG. 1, the operator will grasp handle 12 between the thumb and index finger. With the blade end 14 pointed downward, the knife edge 25 will be used to make a transverse cut through the gel 30 at both ends 28 and 29 of trough 27. Then, with the handle held horizontally and the wire end facing gel tray 26 and the top of U-shaped bend 18 facing upward, wire 13 at bend 18 will be depressed into the thus formed out at 28, gently moved forward to the other end 29 of trough 27 and then moved back to about the midpoint of the trough. The thereby loosened gel strip will be caught up in the U-shaped bend and then can be lifted out of the trough zone. The trough is now ready to be filled with antisera to be incubated in the next step of the immune-electrophoresis operation. A

While particular embodiments of the invention have been illustrated and described, it will be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention, and it is intended to cover in the appended claims all such changes and modifications.

What is claimed is:

1. A gel trough removing tool comprising a finger grippable handle, an elongated, flexible narrow gauge wire extending outwardly from one end and a reduced blade portion terminating in a knife edge at the other end of said handle, said wire terminating in a short U-shaped, downwardly disposed bend transverse to the axis of said wire, said head having an inner width between its vertical legs slightly less than the predetermined width of said 5 trough and the height of the vertical legs of said bend being greater than the predetermined depth of said trough.

2. The gel trough removing tool of Claim 1 in which the knife edge has a length substantially the same as the predetermined width of said trough.

33. The gel trough removing tool of Claim 1 in which the knife edge is transverse to the axis of said wire.

4. The gel trough removing tool of Claim 1 in which said handle comprises a thermoplastic resinous material with one end of said wire embedded therein.

5. The gel trough removing tool of Claim 1 in which said handle comprises a rigid paperboard material with an intermediate portion and one end of said wire embedded therein, and in which said knife edge comprises a U-shaped extension of said wire.

6. A method of removing a gel trough strip in electrophoretic gel media comprising depressing the knife edge of the gel trough removing tool of Claim 1 at both ends of an elongated gel trough and transverse thereto to out said ends, depressing the U-shaped bend of said tool into References Cited UNITED STATES PATENTS 464,141 12/1891 Low 7-143 865,126 1 9/1907 Rosing 714.3 948,861 2/1910 Kailey 7--14.3 3,751,357 8/1973 Rains 204-299 3,762,877 10/1973 Rains et al 204180 G X JOHN H. MACK, Primary Examiner A. C. PRESCOTT, Assistant Examiner,

US. Cl. X.R. 

